Question: What is the indirect cause of the predecessor of street sweepers, janitors, and professionals who take care of buildings such as hospitals and schools?
Paraphrase: What is the circuitous cause of the forerunner of road sweepers, janitors, and experts who watch out of buildings such as clinics and schools?
SPARQL (Wikidata): SELECT ?answer WHERE { wd:Q17309512 wdt:P1479 ?X . ?X wdt:P155 ?answer}